Vehicle-mounted hardened concrete grooving machine

ABSTRACT

A self-contained machine having two cutting heads, a debriscollection system and a ferrous-metal detection system is operable to groove or retexture highway pavements at the rate of 1600 square meters in an 8 hour working day. The cutting heads are driven transversely and in rotation by hydraulic motors along frames which (in use of the machine) extend over a lane width of the highway and which are jacked down onto the pavement surface. The generally dry debris cut from the pavement will be sucked through shrouds covering the cutting head and into the debriscollection system which will return substantially clean air to the ambient atmosphere. Ferrous metal objects like manhole covers will be detected and the cutting heads will be raised and lowered again automatically to avoid them.

United States Patent 11 1 Weaver et al.

[ 1 Dec. 30, 1975 [54] VEHICLE-MOUNTED HARDENED CONCRETE GROOVING MACHINE [75] Inventors: John Weaver, Beaconsfield; David Payne Maynard, Slough; Rayner Walter Taylor, Slough; William Richards Gilbert Bayliss, Slough, all of England [73] Assignee: The Cement and Concrete Association, London, England 22 Filed: Jan. 18, I974 21 Appl. Nd: 434,516

[52] US. Cl 299/39; 51/176 [51] Int. Cl. E01C 23/09 [58] Field of Search ..299/37, 39, 40

[56] References Cited UNITED STATES PATENTS 2,749,103 6/1956 Clemenzi 299/37 X 2,782,017 2/1957 Lewis 1 299/39 2,974,938 3/1961 Lewis... 299/39 3,572,842 3/1971 Mori 299/39 3,703,316 11/1972 Hatcher et al. 299/39 3,767,264 10/1973 Eckey 299/39 Primary Examinen-Ernest R. Purser 57 ABSTRACT A self-contained machine having two cutting heads, a debris-collection system and a ferrous-metal detection system is operable to groove or retexture highway pavements at the rate of 1600 square meters in an 8 hour working day.

The cutting heads are driven transversely and in rotation by hydraulic motors along frames which (in use of the machine) extend over a lane width of the highway and which are jacked down onto the pavement surface.

The generally dry debris cut from the pavement will be sucked through shrouds covering the cutting head and into the debris-collection system which will return substantially clean air to the ambient atmosphere.

Ferrous metal objects like manhole covers will be detected and the cutting heads will be raised and lowered again automatically to avoid them.

12 Claims, 11 Drawing Figures US. Patent Dec. 30, 1975 Sheet 1 of9 3,929,377

& a a w mm Q mm mm mm mm mm US. Patent Dec. 30, 1975 Sheet20f9 3,929,377

US. Patent Dec. 30, 1975 Sheet 3 of9 3,929,377

U.S. Patent Dec. 30, 1975 Sheet 4 f9 3,929,377

U.S. Patent Dec. 30, 1975 Sheet 6 of9 3,929,377

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DCVZ

PFCP

VEHICLE-MOUNTED HARDENED CONCRETE GROOVING MACHINE This invention relates to a vehicle-mounted hardened concrete grooving machine.

It is known thatthe surface of a concrete pavement, which term covers an aerodrome runway and a highspeed road, becomes worn or polished as a result of use. Retexturing of such a surface in order to improve skidding resistance and to improve stability at high speed can be effected in a number of ways which are expensive and/or not acceptable other than perhaps on a small scale. Thus, retexturing has been carried out on the worn surface of a motorway in the United Kingdom by machines operable to cut grooves in the concrete by diamond blades, by silicon carbide blades and by steel flails, respectively (see technical report entitled Treatments to retexture a worn concrete surface of a high-speed road published in March, 1969 by The Cement and Concrete Association). Cutting grooves using diamond impregnated blades and using silicon carbide abrasive blades or discs requires a supply of large quantities of cooling water which necessarily forms a slurry with the particles removed by said blades from the worn surface. This slurry presents two distinct problems, namely, the clogging of the road drainage system by the silt if the slurry is simply permitted to run into the drainage system or the collection of the slurry by special vehicles. If the slurry were to be permitted to lie on the retextured surface so that the water could evaporate, the particles removed by said blades would harden again and would thus tend to nullify, at least partially, the retexturing. On the other hand, the treatment effected by the steel flails is a dry treatment which can be carried out on dry or damp surfaces but a considerable quantity of particulate material is produced which will harden on the road surface if left there.

Furthermore, all of the equipment employed in the actual grooving operations has to be carried to the site on lorries or transporters, and the cooling water for the blades which need to be water-cooled has to be brought to the site in bowsers. These additional operations, including that of slurry collection, and the personnel involved in them, contribute a large proportion of the overall cost of the grooving operation.

Moreover, it would be relatively easy for a machine to be built which would be operable to retexture half a mile of such a worn pavement surface over a width of, say, 12 feet (3.66 metres) per working day but which would need to be carried on a large road-going transporter from site to site. It has been estimated that, at the cost levels prevalent in the United Kingdom in 1972, such a machine would cost something of the order of-1,000 to move by road over a distance of, say, 200 miles from one site to another or from the place of manufacture to a dock. It is felt that such a high cost of transportation of the machine would tend to discourage prospective users of the machine with Great Britain and would also tend to price the machine out of export markets.

The principal object of the present invention is to provide a machine which is operable to retexture the worn surface of a hardened concrete pavement without attendant water bowsers and without separate slurrycollection and pavement-cleaning equipment, and which is such as not to require specialist transportation from one place to another.

Accordingly, the present invention consists in a selfpropelled wheeled motor vehicle which includes a chassis which supports a structure which carries a number of devices which are both movable along said structure and operable to form spaced grooves in the surface of a hardened concrete pavement, said structure being convertible from a first condition thereof in which the motor vehicle is suited for unescorted passage at any speed up to the maximum permitted'speed for said motor vehicle along singleand dualcarriageway roads which are being used'simultaneou'sly'by other motor vehicles to a second condition thereof which is unsuited for such passage along said roads, and vice versa, and said second condition being such that said devices are movable transversely of the motor vehicle along said support and are operable to form said grooves over a pavement width which is greater than the overall width of said motor vehicle.

In a preferred embodiment of said motor vehicle, said structure is fixedly but detachably mounted on said chassis in said first condition and in saidsecond condition thereof, whereby said structure can be readily arranged to extend longitudinally of the motor vehicle in said first condition thereof and transversely of said motor vehicle in said second condition thereof upon detachment thereof from said chassis and subsequent re-attachment thereto. 1'

In an alternative embodiment, said structure is fixedly mounted on said chassis and extends substantially transversely of the motor vehicle in both of said first and said second conditions thereof, said structure furthermore being extensible lengthways of itself to effect said conversion from said first to said second condition thereof. v

Said preferred and alternative embodiments preferably include a debris collection installation which is mounted on said chassis and which includes a motordriven fan operable to produce negative air pressure in a duct which is connected to said structure, whereby the major proportionof the particulate material removed from said pavement in the course of said grooves being formed therein by said devices is collected into said installation under the influence of said negative air pressure.

Said preferred and alternative embodiments also preferably include a ferrous metal detection system operable to detect the presence in a sector of said pavement of ferrous metal objects which are not required to be grooved by said devices.

Said preferred and alternative embodiments further preferably. include at least one engine mounted on said chassis and operable to drive a variable positive displacement hydraulic pump which is hydraulically connected to a variable positive displacement hydraulic motor which is drivingly connected to the driven wheels of the motor vehicle.

The motor vehicle described above may and preferably will also include one or more of the following features:

Said structure, which is supported by the chassis, is preferably bodily displaceable in substantially vertical directions towards or away from said chassis, whereby when said structure is in said second condition thereof and is so bodily displaced the devices carried by said structure are lifted out of contact with the surface of said pavement or are lowered into contact with said surface, respectively. Said structure may be provided with spaced legs whose feet make contact with said 3 pavement surface whenever said devices are lowered into contact with said pavement surface, said legs serving to steady the structure against any undue degree of movement relative to said pavement during the formation of said grooves. Some of said legs may be readily detachable from said structure.

Said structure preferably includes parallel tracks for wheels which are connected to one another by a shaft from which a sub-structure is suspended, said substructure containing said devices and also having ground-contacting wheels, whereby during movement of the devices along the support as aforesaid said wheels run along said tracks and said ground-contacting wheels run along the pavement surface. Such an arrangement will ensure a substantially uniform depth of groove formed in the pavement surface. The substructure may be resiliently connected to the shaft from which it is suspended.

Said devices are preferably of the flail type and driven by a hydraulic motor which is supplied with hydraulic fluid by a hydraulic pump.

There are preferably two sets of devices carried by said structure, each set being contained by a sub-structure constructed in the manner explained above and simultaneously movable in parallel directions to form two sets of grooves in said pavement surface.

By virtue of the fact that the sub-structure(s) is/are movable along the said structure, provision must be made of means connecting the sub-structure to the debris collection installation. A preferred form of said means comprises a manifold connected at one end thereof to one end of the duct which is associated with said fan, said manifold being located in the vicinity of the vertical medial plane of the motor vehicle (namely, that vertical plane which is substantially equidistant from the two sides of the motor vehicle), a continuous channel extending lengthwise of said structure and connected to said manifold, said channel being connected to the other end of said manifold and being open along that face thereof which is directed, in use, towards the pavement surface, flexible flaps being secured by respective one edges thereof to parts of said channel and constituting the means of closing the open side of the channel, the or each sub-structure having an envelope enclosing said devices and so shaped as to provide an upper terminal portion which extends between portions of the respective other edges of said flaps, the arrangement being such that, as the or each sub-structure is moved along the structure with said devices in contact with the pavement surface and being driven to form grooves in said surface, successive portions of said respective other edges of the flaps are parted by the upper terminal portion of the envelope carried by the moving sub-structure, said flaps coacting with each other and with said upper terminal portion to maintain the required degree of negative air pressure within said envelope and manifold to ensure collection of the particulate debris removed from said pavement surface by the devices.

The movements of the devices along the or each sub-structure are effected by a hydraulic motor whose output shaft carries a pinion which meshes with a rack. Said rack may take the form of a drive chain which extends lengthwise of said structure and whose ends are anchored to said structure, thereby acting in the manner of a rack. Preferably, said hydraulic motor operable to cause said movements of the or each sub-structure is supplied with hydraulic fluid from a hydraulic pump which is driven by an auxiliary engine which is different from said one engine.

The debris-collection installation may comprise a box-like structure through which debris-laden air is drawn and cleaned substantially clean air being discharged from the exhaust end of the installation.

Within the box-like structure, the debris-laden air passes through three distinct but consecutive phases of cleaning. In the first phase, the debris-laden air is caused to decelerate, whereby the heaviest particles entrained by the air fall under the influence of gravity onto a conveyor which is operable to convey said particles to a storage bin. These heaviest particles will be quite dry and preferably the conveyor will be a rotatable screw conveyor.

In the second phase, the partially cleaned debrisladen air will be caused to part with some of the remaining debris by passage of said air over and/or through water and by further deceleration, the debris particles so removed sinking through the water to form a sludge or sediment which becomes deposited on another conveyor which is operable to convey said debris particles to a location from which they can be dumped in said storage bin. Said conveyor will preferably be a slatted conveyor which will be caused to follow a path of travel such that, before said debris particles are so dumped, excess water will be permitted to drain from the sludge or sediment.

In the third phase, the partially cleaned debris-laden air will be caused to rotate in the manner of a vortex within the confines of at least one chamber whose wall or walls is or are kept wet, the arrangement being such that as the debris-laden air whirls around the and along said chamber, the particulate material still entrained in said air is flung centrifugally against said wet wall(s), whereby clean air emerges from the output end of said chamber and the particulate material trapped by the moisture is continuously washed away thereby. Said particulate material which has become trapped by the liquid with which the wall or walls is or are wetted is conveyed by said slatted conveyor to said dumping location.

As a certain amount of debris might be deposited on the pavement surface which might remain uncollected when the or each sub-structure is lifted at the end of each groove-forming pass, it may be desirable to mount on said structure at least one nozzle which is connected to the duct in which there is negative air pressure, the open end of said nozzle being adjacent the pavement surface. Said nozzle will need to be placed at that end of the structure towards which said sub-structure and devices are moved during groove-formation and will be operable to ensure that all debris deposited beyond the reach of the negative air pressure within the sub-structure before said sub-structure is lifted will be collected when the motor vehicle is moved to position the structure in a location in which further grooves can be formed adjacent the previously formed grooves.

The chassis-mounted engine and the hydraulic pump driven by said engine and the hydraulic motor which is hydraulically connected to said pump are controlled by a hydrostatic phasing control which is located in the cab of the motor vehicle.

Said phasing control is connected by a control cable to a control lever on the hydraulic motor, and by another control cable to a clutch assembly.

The clutch assembly is also connected to the control lever on the hydraulic pump which is driven by said engine, and the clutch pedal master cylinder is connected by hydraulic piping to a slave cylinder on the clutch assembly.

A throttle pedal, located in said cab like the clutch pedal and the phasing control to provide a set of motor vehicle controls, is connected to the engine.

The hydraulic pump is hydraulically connected to the hydraulic motor, as already stated, and said motor is operable to drive the driven road wheels (preferably the rear road wheels) of the motor vehicle through a drop gear box.

An auxiliary engine and pump, conveniently mounted adjacent the engine and pump which provide motor vehicle propulsion (forwards or reverse) and also drive of the devices which are operable to form the grooves in the pavement surface, provide the drive for the following:

a. the hydraulic motor driving the fan of the debriscollection installation;

b. the hydraulic motors driving the screw-conveyor and slatted-conveyor in said installation;

c. the hydraulic motor(s) driving the sub-structure(s) I movable along the structure(s) on the grooveforming and return passes;

d. a water circulation pump in said installation;

e. hydraulic jacks which are operable to raise and lower the structures from which the sub-structures are suspended;

f. hydraulic jacks which are operable to raise and lower the storage bin (mentioned above) into whichall collected debris is fed or dumped. The jacks can deal with empty and filled bins;

g. a hydraulic brake which is brought into operation automatically when'said structures are lowered to begin the groove-forming operation, said brake acting to keep the motor vehicle stationary during groove formation. Y

The ferrous metal detector heads is or are located in advance of (in relation to the normal direction of travel of the motor vehicle) the leading one of the two structures from which sub-structures depend. This normal direction of travel will be forwardly (ignoring small rearwards movements for the purpose of corrective adjustments) because, after a set or sets of grooves has or have been formed in the pavement surface, the driver of the motor vehicle will be required to move the motor vehicle in order to re-position the devices which are operable to form the grooves during the next pass.

It will be generally convenient therefore to position the detector head or heads slightly to the rear of the front wheels of the motor vehicle,

The system includes a memory in which willbe stored information relating to the position of any ferrous metal object detected. The system will operate to permit groove-formation by said devices except over an area of the pavement surface in the relatively immediate vicinity of the object. Thus, by way of example, if the object which has been previously detected is located about half-way along one pass of the devices, the structure which supports the sub-structure containing the devices will be lowered and the sub-structure will be moved in order to permit the devices to form the grooves in the pavement surface, said structure being automatically lifted when the critical distance of the devices from the object has been reached and being automatically lowered again when said object has been passed over.

appended claims. The invention itself, however, both as to its organization and its method of operation, to-

gether with additional objects and advantages thereof,

will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings, wherein like reference 7 characters indicate like parts throughout the several figures, and in which:

FIG. 1 illustrates diagrammatically a top plan view of one embodiment of a motor vehicle constructed in accordance with the present invention;

FIG. 2 illustrates aside elevation of the vehicle illustrated in FIG. 1; I

FIGS. 3 and 4 are diagrammatic front and rear end elevations of said motor vehicle, FIG. 3 illustrating said vehicle in its road-going configuration and FIG. 4 illustrating said vehicle in its groove-forming configuration;

FIG. 5 illustrates diagrammatically the manner in which some of the controls in the vehicle cab are connected to various elements which are operable to move the vehicle;

FIG. 6 illustrates diagrammatically means visible to the driver of the vehicle for the accurate control of positioning of the vehicle at the end of each traverse of at least one cutting head with which the vehicle isprovided for the purpose of grooving the worn surface of a hardened concrete road;

FIG. 7 illustrates diagrammatically the physical relationship between the ferrous-metal detectors and the cutting head or heads with which the vehicle is provided;

FIG 8 illustrates the manner in which the cutting heads coact with limit switches; and

FIG. 9 is a key to the various components which are illustrated in FIGS. 10 and 11 which together illustrate a complete hydraulic circuit diagram for the vehicle.

The present invention will now be more particularly described with reference to the accompanying drawings in which there is illustrated one embodiment of self-propelled wheeled motor vehicle according to the present invention. Said vehicle will be seen to comprise a chassis 10 provided with pneumatic tyred wheels 11. Said chassis is formed from substantial I-section girders welded to one another to form a strong unit, the electrical wiring and hydraulic conduits being accommodated where feasible within the cavities or re-entrant portions of said girders and being concealed from view (where necessary) by detachable covers.

At the front end of the vehicle there is a cab 12 for the accommodation of a driver and co-driver. Behind the cab 12, there is located a tank or reservoir 13 for all the hydraulic fluid and then a main diesel prime mover 14 and an auxiliary diesel prime move 15. A debris-collection system indicated generally by the reference numeral 16 includes a fan unit 17 whose fan is driven by a fixed capacity motor 18. Said fan draws air through a box-like member l9,said air entering said 7 member at 20 and being returned to the ambientatmosphere at 21 and being caused (between those two locations) to undergo cleaning operations as and for the purpose hereinafter described.

Attached to a flanged pipe which constitutes the air intake 20 is one end of a pipe 22 whose other end is attached to a main duct 23 which is connected pneumatically by way of manifold 28 to each of two subsidiary ducts 24, 25 which are, in turn, connected to manifolds 26, 27, respectively.

Two structures 35, 36 are supported by the chassis and, as drawn in most of the Figures of the accompanying drawings, extend parallel to one another transversely of the vehicle, namely, in the second of saidtwo alternative conditions of each of said structures-Each of said structures comprises essentially a rectangular frame having parallel frame elements 37 whose ends are joined to one another by parallel end elements 38. Spaced pairs of supports 40 are provided whichare connected to the frame elements 37 (e.g. by welding) and also to be respective manifolds 26, 27 which are in the form of channels having interconnected side walls 41 and top wall 42 and the fourth wall being made of flexible flaps 43. Thus, the structures 35, 36, consisting as they do of welded and/or bolted steel components, are very strong and are carried on the chassis by hydraulic cylinder actuators 44, 45 .when said structures are in said second conditions thereof and are provided with spaced legs 46. The legs 46 are located in pairs at opposite ends of the structures serve to steady said structures and the actuators 44, 45 are for raising and lowering the structures as and for the purpose hereinafter explained.

The frame elements 37 provide .parallel tracks for wheels 50 which are connected to the opposite ends of a shaft 51 from which a so-called sub-structure 52 is suspended. The shaft 51 is driven by a fixed capacity motor 53 and has, spaced axially along the shaft, pinions 54 meshing with corresponding racks 55. The.

sub-structure 52 runs on the ground on wheels 56,. It

will be understood, therefore, that rotation of the shaft.

51 by the motor 53 will cause the sub-structure 52 to move lengthwise of the relevant one of the structures 35, 36 and transversely of the vehicle. 1 Each sub-structure 52 contains devices which ar operable to form spaced grooves in the surface-bf a hardened concretepavement and said devices form part of a cutting head 60 driven by a fixed capacity motor 61. The cutting head incorporates tungsten-carbide-tipped flails and is generally constructed in accordance with US. Pat. No. 3,659,722. It will be understood of course, that the basic frame, power source, guide handle and so on of the machine for treating surfaces disclosed in said Patent are not necessary in the apparatus according to the present invention.

Said cutting heads 60 are substantially enclosed by an When the debris-laden air is drawn through the ducts 25, 24, 23 and through the pipe 22 into the box-like member 19, said air immediately decelerates because it enters a chamber larger than that along which it has been travelling and the largest pieces of debris fall onto the screw conveyor 70 which is driven by a fixed capacity motor 71, that end of said conveyor which is remote from the motor 71 being supported for rotation about its axis in any convenient manner and also projecting over a debris skip or container 72 so that said largest pieces of debris will be fed continuously thereto.

The partially cleaned debris-laden air is then caused to part with some of the remaining debris by passage of said air over and through water and by further deceleration as a result of expansion, the debris particles so I removed sinking through the water to form a sludge or envelope whose bottom edge is close to the ground and sediment which becomes deposited on another conveyor which is driven by a fixed capacity motor 73 and an associated drive which includes two shaft-mounted sheaves 74, 75 and a drive belt 76, said other conveyor being operable to convey the sludge or sediment to a location which is indicated generally by the reference numeral 77 at which it is dumped into the skip 72. Said other conveyor will preferably be such (for example a slatted conveyor) and will preferably be forced to follow a path of travel at a speed such that excess water will be permitted to drain from said sludge or sediment.

Thereafter, the partially cleaned debris-laden air is fed into a so-called Type R Roto-Clone 78 manufactured by American Air Filter Company Incorporated and by its United Kingdom subsidiary company, A.A.F. Limited. Said apparatus 78 includes the dust separators which are the subject of US. Pat. No. 3,236,031 and the construction and operation of said separatorswill not therefore be discussed here. The water necessary to the cleaning system is pumped through pipework 79 into the liquid supply unit 6 of the dust separators disclosed in said Patent Specification by a pump 80 which is driven by a fixed capacity motor 81.

The virtually completely cleaned air emerges from the clean air outlet of the apparatus 78 and is fed therefrom by way of a duct 82 into the exhaust 21.

The propulsion of the motor vehicle is effected by the prime mover 14 driving an hydraulic pump which is hydraulically connected to an hydraulic motor 91 which is connected to the rear wheels 11 of the vehicle through a drop gear box 92 and propeller shaft 93.

The cab 12 of the vehicle is provided with a simple set of controls which have been deliberately created to simulate conventional road-vehicle controls insofar as the operator is concerned and this was felt to be very important because the necessity for specialist training of driver/operators for the machine is completely avoided. Thus, the cab 12 contains a clutch pedal whose master cylinder 101 is hydraulically connected to a slave cylinder 102 which forms part of a clutch assembly. The cab also contains a throttle pedal 103 connected to the prime mover 14 and a Morse hydrostatic phasing control indicated by the reference numeral 104. Said phasing control is a single lever control unit for sequential actuation of at least two force-transmitting devices and the construction and operation of said phasing control is known from US. Pat. No. 3,530,736 and it will suffice for present purposes only to point out that, in the vehicle according to the present invention, it was not desired to connect the two pushpull control cables respectively to the motor and the pump. Thus, the relevant end of a control cable 105 of the phasing control 104 is connected to a lever 106 and said lever 106 is provided with a longitudinal slot therein (not illustrated) along which there is movable a pin connection between said lever 106 and another lever 107. The lever 106 is mounted for angular movements about the axis 108 and the axis of said pin'connection can be brought into axial alignment with said axis 108 by means of actuation of the slave cylinder 102 to lift said lever 107 upwardly to compress a helical compression spring 109, said lever 107 being connected at 120 to an extension 121 of the ram which is connected to the piston in said slave cylinder 102 and said extension 121 also being operatively connected to said extension 121 by an abutment plate 122 which constitutes the abutment for one end of said spring 109. The other end of said spring abuts against a plate 123 which is carried by a plate 124 which is conveniently mounted on a part of the vehicle chassis. The lever 107 is also connected to the control lever on the pump 90 by a connection 130.

The relevant end of the other control cable of the phasing control, namely, control cable 131, is connected to the control lever of the hydraulic motor 91.

With the clutch pedal 100 depressed, the axis of the pin connection between the levers 106 and 107 is brought into axial alignment with the axis 108, the pump is set to zero swash. If said clutch pedal is now slowly released, the lever 107 will slide downwards relative to the lever 106 and will gradually stroke" the pump 90 to give drive to the vehicle by way of the motor 91, the gear box 92 and the propeller shaft 93.

For road travel, the phasing control 104 is used-as a gear selector in the following manner:

The clutch pedal 100 should be depressed firstly and then the phasing control lever 132 is appropriately moved to select forwards or reverse. The clutch pedal should now be allowed to ease upwardly simultaneous with the throttle pedal 103 being depressed, thereby following conventional driving technique. The speed of the vehicle over the ground can now be controlled by moving the phasing control lever 132 further forward (high gear) and/or by depressing the throttle pedal.

As to stopping procedures, for a normal stop the throttle pedal 103 is allowed to rise and, as the vehicle slows down, the clutch pedal 100 is depressed. Neutral position of the phasing control lever 132 is selected and the clutch pedal can be released again.

For an emergency stop, both the clutch pedal 100 and a brake pedal are depressed simultaneously in the usual way.

For work on a site, where it is only required to inch the vehicle forwards from the location at which grooves have been formed by the two cutting heads (which incidentally, travel in opposite directions along their respective structures 35, 36) to the next location at which more grooves are to be cut, the speed being say, 4-5 m.p.h., the clutch assembly may be set to give a restricted stroke of the control lever of the pump 90 with the result that all transmission control can be done by using the phasing control lever 132; that is to say, with the clutch pedal 100 released, appropriate movement of the lever 132 will stroke the pump 90 in forward or in reverse as required. With the lever 107 set to restricted stroke, the phasing control 104 has a mechanical advantage over the control lever of the pump 90 and full movement of the phasing control lever 132 may be used for only a limited movement of the pump 10 control lever, thereby obtaining a very sensitive control of the vehicle transmission at low speed.

The prime mover 14 drives two variable capacity pumps 143 which are hydraulically connected to the respective motors 61 which drive the cutting heads.

The auxiliary prime mover 15 drives a variable capacity pump which is hydraulically connected to the fan motor 18, and also drives a variable capacity pump 141 with pressure over-ride. Moreover, said prime mover also drives a fixed capacity pump 142 which is a charge pump for the main system with which the pump 141 is also associated. Said main system provies the hydraulic force for the hydraulic motors 53, 71 and 73 and for the hydraulic motor 81 which drives said water circulation pump 80 and for the hydraulic jacks 44, 45 which are operable to raise and lower the structures 35, 36 when the vehicle needs to be moved ends are connected chains 153 which are also connected to the skip 72 by means of a pair of spreader bars 154 whose opposite ends 155 are shaped to engage legs 156 on said skip. Lastly, the said main system provides an hydraulic brake (not illustrated) which is automatically brought intooperation when the structures 35, 36 start to be forceddownwardly by the jacks 44, 45 prior to the next groove-forming operation, said brake being necessary to help to maintain the vehicle stationary during groove formation; in fact, the force applied by the hydraulically operated jacks 44, 45 to the feet of the spaced legs 46 of the structures 35, 36 in contact with the ground is such that a large proportion of the entire weight of the vehicle is even taken off the tyred wheels 11 so that, with the hydraulic brake, the chances of the vehicle moving are nil.

The cab 12 contains a console 160 which supports many of the visual indicators with which the vehicle is provided but with which the invention is not concerned. Said console also supports a rotatable marker disc 161 whose periphery is marked with a white line at positions indicated by 162, 163, the console being formed to provide a slit 164 through which the one or other of said white lines is visible at certain times as hereinafter explained. A shaft 165 carries 'two toothed wheels which are spaced apart along the rotational axis of said shaft. One of said two toothed wheels on said shaft 165 is drivingly connected to a toothed wheel 166 by a toothed belt 167, the wheel 166 being fixed to or integral with the marker disc 161. The other of said two toothed wheels on said shaft 165 is drivingly connected by a toothed belt 173 to a toothed wheel 170 which is fixed to or integral with a wheel 171 which is supported at one end of an arm 172 which is mounted for free angular movements about the rotational axis of the shaft 165. The wheel 171 has a tyre made of polyurethane and the circumference of said tyre is 30 inches and, in the position illustrated, said tyre is in contact with the ground and will roll along the ground when the vehicle is moved along the ground. One revolution of the wheel 171 is equivalent to one path width of a cutting head 60 (each cutting head being 750 mm in axial length and the two cutting heads having a space, measured longitudinally of the vehicle, of 750 mm between them) and the toothed wheels 166, 170 and the two toothed wheels on the shaft 165 and the toothed belts 167, 173 are such that there is a 4:1 reduction between the wheel 171 and the disc 161.

The white lines at 162, 163 are each one sixteenth of one inch wide (i.e. measured circumferentially of the disc 161) and the vehicle will have travelled an inch along the ground during the angular movement of the disc 161 necessary to make the white line move from the angular setting thereof in which it has just become visible to the driver in the window l64 to the angular setting thereof in which it has just disappeared from the window. The driver must aim to position the vehicle so that a white line is central in the window 164 but provided that any part of the relevant white line can be seen by the driver in said window the vehicle will be positioned within one half of an inch of the requisite position. Consequently, groove-forming will be permissible.

It will be appreciated that, as the cutting heads 60 are 750 mm wide (i.e. axial dimension) and are spaced apart by 750 mm, it will be necessary for the vehicle to be moved alternately 2 feet 6 inches and 7 feet 6 inches, and this is reflected in the fact that the disc 161 has to be turned clockwise through 90 to bring the white line at 163 to the window 164 and that the disc 161 has to be turned clockwise through 270 to bring the white line at 162 to the window once again.

Devices will be provided which will give the driver of the vehicle both a visual signal and an audible signal advising him that the structures 35, 36 have been raised by the jacks 44, 45 and that he must advance the vehicle.

The swinging arm 172 is retractable by means of a cable extending through a hole in the floor of the cab 12 andfastened by one of its ends to said arm. The other end is provided with a handle to facilitate lifting of said arm by the driver or co-driver and said handle can be engaged by any suitable device to keep the swinging arm in its hoisted position.

Obviously, ferrous metal objects may have been incorporated into highways and it is desirable if not essential for the machine to avoid grooving the metal objects. The system by which this desirable object or requirement is achieved will now be described:

The requirement of the system is to enable each of the two independently moving concrete cutting heads 60 to be raised when ferrous metal has been detected, to avoid damage to the cutters. The system consists of an assembly of eight detector elements 180 each 457 mm (18 in.) in length, making a total of 3.66 m (12 ft.) end to end, (see FIG. 1) and a control box which includes relays for controlling the raising of the main cutting heads.

The detector elements 180 are placed 1.1 metres (45 in.) ahead of the leading cutting head 60 (Le. 1% widths), and their function is to detect ferrous metal objects which may coincide with either of the cutting swathes. In view of the irregular cutting sequence dictated by the gap between the two cutting heads, electronic logic has been introduced to determine which head will be affected by any piece of detected metal.

The progression of the cutting heads 60 also needs information about the longitudinal distance the vehicle has moved and this is provided by a single pole double way microswitch attached to the marker disc 171 which provides one pulse per rotation, corresponding to a forward movement of one cutting head width. This pulse is used to clock the electronic system.

The eight elements are mounted in longitudinal juxtaposition to cover a twelve foot length and, in order to maintain optimum detection sensitivity across the ends of adjacent elements, the ferrite bar magnets must be mounted with NN or 8-8 between the adjacent faces.

When the vehicle has been mechanically set up to perform grooving operations but without being in position for the first cuts, the ferrous metal detector will be switched on. The elements 180 will be activated by a special test piece or by a shovel passed along the undersides of said elements 180, passage of said piece or of said shovel diverting the magnetic field and causing the relevant magnetic reed contact to open.

Thereafter, during normal operation of the vehicle to cut grooves, the cutting heads will be raised only as often as required by the occurrence of objects like drain covers, reflective road studs, commonly called cats eyes and so on. Whenever the so-called electronic logic or memory dictates, the appropriate one of a number of lift-control microswitches 181 operated by a ramp 182 operates to cause the relevant structure 35 or 36, or possibly both of them if the metallic object were to be very long, to be lifted in order to raise the relevant cutting head 60.

The rear springs are placed axially outwardly of the brakes which are housed within an extension of the differential casing at 191, this being done to provide the greatest possible distance between spring centres because of the large burden carried by the motor vehicle and particularly over the rear wheels. So by placing said springs, we have increased the distance between spring centres by about 12 inches (compared with that in conventional layouts) in the vehicle according to the present invention whose overall width is 8 feet 2% inches.

The hydraulic jacks 44, 45 are permanently connected to the chassis 10 in any convenient manner and the free end of the ram of each jack is detachably connected to the relevant one of the structures 35, 36 at a location which is indicated by the reference numeral 195. Said connection may consist of a bifurcated element in the two limbs of which there are aligned holes, the free end of the ram being appropriately apertured so that the aperture through the ram can be lined up with the holes in the limbs of said bifurcated element and a connecting pin pushed into said aligned holes and aperture. The position of said pin is maintained by circlips or other similar fastening devices. The above described arrangement is the one which is adopted when the vehicle is in its groove-forming configuration, namely, with the structures 35, 36 extending transversely of the vehicle. When the vehicle is required to assume its road-going configuration to travel, say, from one site to another, the detachable connection referred to above is undone and the structures 35, 36 are placed under the chassis 10 extending parallel to the medial line of the vehicle. Thereafter, the structures are connected to the chassis in such a manner that they are safely stowed or slung under the prime movers 14, 15.

The provision of the flexible flaps 43 whose free edges are held together partially by the springiness of the elastomeric material from which the flaps are made and partially by the suction created by the fan is an important feature of the invention because said flaps enable the debris-laden air to be efficiently drawn into the air-cleaning part of the machine. The efficiency of operation of this part of the machine is in no small measure contributed to by the streamlined or faired shape of the upper portion 65, 66. That upper portion not only parts the free edges of said flaps 43 as the cutting head 60 is traversed but also the requisite degree of scaling is provided both at the leading end and at the trailing end of said upper portion to ensure proper pick-up of the material which has been removed from the pavement surface. It will be appreciated that, without an adequate degree of sealing between the flexibleflaps and said upper portion 65, 66, the suction within the envelope which encloses each cutting head 60 would be insufficient to pick up the debris and said debris would therefore remain on the pavement surface, where it would harden again.

One version of the motor vehicle described above is 8 feet 2% inches wide and 36 feet long and is capable of moving along normal roads, simultaneously with other road traffic; at forward speeds up to 30 m.p.h. The motor vehicle is such that it will physically be capable of using normal roads without police escort ever being necessary. on some of the more narrow roads; police escort is nearly always necessary for heavy goods vehicles which are carrying extra-wide loads or which are extra-wide themselves.

By making the structures 35, 36 convertible in the manner described above, the overall width of the motor vehicle can be as stated and yet the length of each of said structures can be feet in the case of the motor vehicle whose width is 8 feet 2% inches. With a structure length of 15 feet, the grooving machine constituted by said motor vehicle is expected to be able to form two spaced sets of parallel grooves in a pavement surface at a minimum speed of 12 feet per minute and simultaneously. The maximum operating cycle time is expected to be 90 seconds, that is, 90 seconds elapse from the start of one groove-forming operation until the start of the next groove-forming operation, the entire cycle being inclusive of raising the structures 35, 36 at the end of the groove-forming pass and bringing the cutting heads 60 back to the respective starting positions thereof on said structures and then lowering the structures again.

The grooving machine described above should, it is thought be capable of retexturing the hardened concrete surface of a pavement at the rate of 12 feet X half a mile per working day. During such operations, an estimated 6-l0 tons of particulate material will be removed. The storage bins which are to be employed for this debris will be standard storage bins capable of being picked up full from and deposited empty on the highway pavement itself by standard vehicles. Thus, it is considered that two such storage bins will be filled per day during groove-forming operations and it will be possible for a company operating debris disposal vehicles to place empty storage bins at approximately correct intervals along a highway pavement and to pick up filled storage bins from those locations, these placing and picking up operations being carried out at times which will suit the said company and quite independently of the times at which the motor vehicle will substitute'an empty storage bin for a filled one.This will ensure economical groove-forming operations because the grooving machine will not be forced to wait for an empty storage bin in order to continue operations.

lt an aerodrome runway is being retextured and if an emergency is declared involving an incoming aircraft, the motor vehicle can quickly clear the runway simply by the driver operating the relevant controls to lift the structures 35, 36 and to drive the vehicle at speed off the runway, leaving it clear and free from debris. This could hardly be achieved by any grooving machine of the kind which would need to be carried on a special transporter from site to site and which was designed only to travel at the low speed (say 4-5 m.p.h.) needed on the site and which required a large amount of ancillary plant.

The substantially complete cleansing of the debrisladen air drawn into the debris collection installation will mean that retexturing of any hardened concrete pavement surface will not be objectionable for example to other road users, farmers and owners of private houses, all of whom might be inconvenienced by the dposition of large quantities of debris on their vehicles, land and stock, houses and so on, respectively.

The use, in the controls which will need to be operated by the driver of the vehicle, of a brake and a clutch and a throttle will greatly assist training of the driver who will be presented with a collection of controls which will be familiar to him in a broad sense. It will be necessary to teach him in what manner the phasing control and the clutch and throttle pedal are to be operated to produce the required results but it is thought that they are sufficiently familiar to known control systems to cause little or no training and operating difficulties.

What we claim as our invention and desire to secur by Letters Patent of the U.S. is:

l. A vehicle constituting a self-contained grooving machine which comprises:

a. a vehicle chassis and roadway-engaging wheels for enabling said vehicle to be moved longitudinally of the roadway;

b. a supporting structure carried by said chassis comprising parallel tracks extending transversely both of said chassis and of said direction of movement of said vehicle along the roadway;

c. cutter means movable along said tracks in engagement with the roadway surface and operable to form at least two parallel grooves simultaneously in said roadway by a dry cutting action, said grooves extending transversely of said roadway;

d. roadway-surface cleaning means operable to pick up substantially all of the dry particulate material removed by said cutter means during the formation of said at least two grooves; said cleaning means comprising fan means and a deceleration chamber and an envelope all of which are interconnected by a pneumatic circuit said envelope enshrouding said cutter means and having a lower terminal edge closely adjacent to the roadway surface and said deceleration chamber being interposed in the pneumatic circuit between the fan means and the envelope;

f. said fan having intake and output apertures and being operable to produce negative air pressure at its intake aperture in order to create an airflow under said lower terminal edge towards said output aperture for the purpose of entraining substantially all of the dry particulate material removed by said cutting action from said roadway;

g. said pneumatic circuit including a manifold channel disposed above and parallel to said tracks on 'the supporting structure said channel being rigid and of inverted U-shape, the open bottom of said channel being closed by two elongated flexible roadwayflaps of elastomeric material, the upper portion of said envelope extending between said contacting portions of the flaps and said envelope moving along said channel as said cutter means moves along said tracks during groove formation, the resilience of the elastomeric material coupled with a negative air pressure within the channel ensuring an adequate degree of fluid-tightness between said flaps and around said upper portion of the envelope.

2. Avvehicle constituting a roadway grooving machine according to claim 1 wherein is additionally provided a replaceable debris-collecting device supported by said chassis; and conveyor means associated with said deceleration chamber and drive means therefor, whereby air with entrained particulate material and entering said deceleration chamber decelerates and some of the entrained particulate material falls on said conveyor and is conveyed thereby to the debris-collecting device.

3. A vehicle constituting a roadway grooving machine according to claim 1 wherein said cleaning means further includes a vortex chamber and means for centrifugally rotating debris-laden air in said vortex chamber to separate the debris from the air.

4. A vehicle according to claim 1 wherein said supporting structure is detachably supported by said chassis in a first position transverse to the chassis and protruding from its side for the purpose of cutting'said grooves over a pavement width which is greater than said overall width of the vehicle, and said supporting structure being removable from its first position and being detachably'securable in a second position under and longitudinally of said chassis rendering said vehicle suitable for travel longitudinally along a roadway.

5. A vehicle according to claim l, wherein is provided means for detecting and signaling the presence of metal objects in the roadway carried by such chassis in advance of the cutter means, said supporting structure including means for selectively raising or lowering such cutting means with respect to said chassis and roadway surface in accordance with the presence or absence of metal objects as signaled by said detecting means in order selectively to disengage or to engage said cutter means with the roadway surface.

6. A vehicle as claimed in claim 1, wherein fluidoperated jacking means are mounted on said chassis at corresponding locations on opposite sides of the vehicle, said jacking means including rams displaceable vertically in relation to the chassis and each of which has a free end, spaced fixing locations on said supporting structure, the free end of one of said rams being detachably connectible to one said fixing locations and the free end of the other of said rams being detachably connectible to the other of said fixing locations, whereby said supporting structure can be raised and lowered to bring the groove-forming devices out of and into contact, respectively, with said pavement surface.

7. A vehicle as claimed in claim 1, wherein said cutter means are constituted by flails, rotatable support means for said flails, drive means operable to rotate said support means about an axis to cause said flails to hit said pavement surface, said flails being so connected to support means that they are free to recoil upon hitting said pavement surface and are capable of resuming their substantially radial dispositions with respect to said axis before they next hit said pavement surface.

8. A vehicle as claimed in claim 1, which includes at least one prime mover, a first pump driven by said prime mover, a motor hydraulically connected to said first pump, two vehicle wheels connected to one another by a shaft, said motor being operatively connected to said shaft, and a supply of hydraulic fluid, whereby the said two vehicle wheels are driven by a hydrostatic transmission.

9. A vehicle as claimed in claim 8, wherein said cutter means are carried by groove cutting devices, there being a second pump driven by said prime mover, a second motor hydraulically connected to said second pump, a second shaft, said second shaft being operatively connected to said groove cutting devices and to said second motor, whereby said devices are driven by a hydrostatic transmission.

10. A vehicle as claimed in claim 8, which further includes a clutch, a single lever control unit for sequential actuation of at least two force transmitting devices, cable means connecting said control unit directly to a control lever of said motor, second cable means connecting said control unit to a control lever of said first pump by way of said clutch, the arrangement being such that said clutch is operable to set the first pump to zero swash and is thereafter releasable to stroke the first pump to give drive to said wheels by way of said shaft.

11. A vehicle as claimed in claim 10, wherein the control unit is for use as a gear selector.

' 12. A vehicle constituting a self-contained roadwaygrooving machine which comprises:

a. a vehicle chassis and roadway-engaging wheels for enabling said vehicle to be moved longitudinally of the roadway;

b. a supporting structure carried by said chassis comprising a track extending transversely both of said chassis and of said direction of movement of said vehicle along the roadway;

c. cutter means movable along said track in engagement with the roadway surface and operable to form a groove transversely of said roadway by a dry cutting action;

d. roadway-surface cleaning means operable to pick up substantially all of the dry particulate material removed by said cutter means during the formation of said groove;

. said cleaning means comprising suction means including a manifold mounted on the chassis connected to an envelope enshrouding said cutter means and having a lower terminal edge closely adjacent to the roadway surface;

f. said manifold having a slot disposed above and parallel to said track on the supporting structure, said slot being closed by flexible flaps, the upper portion of said envelope extending between said flaps and moving along said slot as said cutter means moves along said track during groove formation. 

1. A vehicle constituting a self-contained roadway-grooving machine which comprises: a. a vehicle chassis and roadway-engaging wheels for enabling said vehicle to be moved longitudinally of the roadway; b. a supporting structure carried by said chassis comprising parallel tracks extending transversely both of said chassis and of said direction of movement of said vehicle along the roadway; c. cutter means movable along said tracks in engagement with the roadway surface and operable to form at least two parallel grooves simultaneously in said roadway by a dry cutting action, said grooves extending transversely of said roadway; d. roadway-surface cleaning means operable to pick up substantially all of the dry particulate material removed by said cutter means during the formation of said at least two grooves; e. said cleaning means comprising fan means and a deceleration chamber and an envelope all of which are interconnected by a pneumatic circuit said envelope enshrouding said cutter means and having a lower terminal edge closely adjacent to the roadway surface and said deceleration chamber being interposed in the pneumatic circuit between the fan means and the envelope; f. said fan having intake and output apertures and being operable to produce negative air pressure at its intake aperture in order to create an airflow under said lower terminal edge towards said output aperture for the purpose of entraining substantially all of the dry particulate material removed by said cutting action from said roadway; g. said pneumatic circuit including a manifold channel disposed above and parallel to said tracks on the supporting structure said channel being rigid and of inverted U-shape, the open bottom of said channel being closed by two elongated flexible flaps of elastomeric material, the upper portion of said envelope extending between said contacting portions of the flaps and said envelope moving along said channel as said cutter means moves along said tracks during groove formation, the resilience of the elastomeric material coupled with a negative air pressure within the channel ensuring an adequate degree of fluid-tightness between said flaps and around said upper portion of the envelope.
 2. A vehicle constituting a roadway grooving machine according to claim 1 wherein is additionally provided a replaceable debris-collecting device supported by said chassis; and conveyor means associated with said deceleration chamber and drive means therefor, whereby air with entrained particulate material and entering said deceleration chamber decelerates and some of the entrained particulate material falls on said conveyor and is conveyed thereby to the debris-collecting device.
 3. A vehicle constituting a roadway grooving machine according to claim 1 wherein said cleaning means further includes a vortex chamber and means for centrifugally rotating debris-laden air in said vortex chamber to separate the debris from the air.
 4. A vehicle according to claim 1 wherein said supporting structure is detachably supported by said chassis in a first position transverse to the chassis and protruding from its side for the purpose of cutting said grooves over a pavement width which is greater than said overall width of the vehicle, and said supporting structure being removable from its first position and being detachably securable in a second position under and longitudinally of said chassis rendering said vehicle suitable for travel longitudinally along a roadway.
 5. A vehicle according to claim 1, wherein is provided means for detecting and signaling the presence of metal objects in the roadway carried by such chassis in advance of the cutter means, said supporting structure including means for selectively raising or lowering such cutting means with respect to said chassis and roadway surface in accordance with the presence or absence of metal objects as signaled by said detecting means in order selectively to disengage or to engage said cutter means with the roadway surface.
 6. A vehicle as claimed in claim 1, wherein fluid-operated jacking means are mounted on said chassis at corresponding locations on opposite sides of the vehicle, said jacking means including rams displaceable vertically in relation to the chassis and each of which has a free end, spaced fixing locations on said supporting structure, the free end of one of said rams being detachably connectible to one said fixing locations and the free end of the other of said rams being detachably connectible to the other of said fixing locations, whereby said supporting structure can be raised and lowered to bring the groove-forming devices out of and into contact, respectively, with said pavement surface.
 7. A vehicle as claimed in claim 1, wherein said cutter means are constituted by flails, rotatable support means for said flails, drive means operable to rotate said support means about an axis to cause said flails to hit said pavement surface, said flails being so connected to support means that they are free to recoil upon hitting said pavement surface and are capable of resuming their substantially radial dispositions with respect to said axis before they next hit said pavement surface.
 8. A vehicle as claimed in claim 1, which includes at least one prime mover, a first pump driven by said prime mover, a motor hydraulically connected to said first pump, two vehicle wheels connected to one another by a shaft, said motor being operatively connected to said shaft, and a supply of hydraulic fluid, whereby the said two vehicle wheels are driven by a hydrostatic transmission.
 9. A vehicle as claimed in claim 8, wherein said cutter means are carried by groove cutting devices, there being a second pump driven by said prime mover, a second motor hydraulically connected to said second pump, a second shaft, said second shaft being operatively connected to said groove cutting devices and to said second motor, whereby said devices are driven by a hydrostatic transmission.
 10. A vehicle as claimed in claim 8, which further includes a clutch, a single lever control unit for sequential actuation of at least two force transmitting devices, cable means connecting said control unit directly to a control lever of said motor, second cable means connecting said control unit to a control lever of said first pump by way of said clutch, the arrangement being such that said clutch is operable to set the first pump to zero swash and is thereafter releasable to stroke the first pump to give drive to said wheels by way of said shaft.
 11. A vehicle as claimed in claim 10, wherein the control unit is for use as a gear selector.
 12. A vehicle constituting a self-contained roadway-grooving machine which comprises: a. a vehicle chassis and roadway-engaging wheels for enabling said vehicle to be moved longitudinally of the roadway; b. a supporting structure carried by said chassis comprising a track extending transversely both of said chassis and of said direction of movement of said vehicle along the roadway; c. cutter means movable along said track in engagement with the roadway surface and operable to form a groove transversely of said roadway by a dry cutting action; d. roadway-surface cleaning means operable to pick up substantially all of the dry particulate material removed by said cutter means during the formation of said groove; e. said cleaning means comprising suction means including a manifold mounted on the chassis connected to an envelope enshrouding said cutter means and having a lower terminal edge closely adjacent to the roadway surface; f. said manifold having a slot disposed above and parallel to said track on the supporting structure, said slot being closed by flexible flaps, the upper portion of said envelope extending between said flaps and moving along said slot as said cutter means moves along said track during groove formation. 